1. Field of the Invention
The present invention relates to a magnetic recording/reproducing apparatus. Particularly, the invention is concerned with a loading and unloading mechanism for a cartridge with a magnetic tape received therein.
2. Description of the Prior Art
A conventional magnetic recording/reproducing apparatus 21 will be described below with reference to FIG. 24 which is a plan view of the apparatus, FIG. 25A which is a sectional view taken on line A--A in FIG. 24, and FIG. 25B which is a side view of a principal portion thereof.
In the conventional magnetic recording/reproducing apparatus 21 (hereinafter referred to as the "apparatus 21"), a pair of guide members 21b and 21c each having a U-shaped groove are attached in an opposed relation to each other to right and left side faces of a base plate 21a.
In the vicinity of the guide members 21b and 21c, openings 21d are formed in portions of the base plate 21a, as shown in FIG. 25A.
On the back of the base plate 21a are mounted a pair of plate springs 22 having a strong resilience, the plate springs 22 being screwed at one end thereof and free at the opposite end. At the tip of the free end of each plate spring 22 is formed a retaining portion 22a and a roller 22b is supported rotatably by the retaining portion 22a.
The roller 22b is inserted into the associated opening 21d of the base plate 21a. When a strong depressing force is applied to the roller 22b, the strong resilience of the plate spring 22 permits the roller 22b to move vertically within the opening 21d with the foregoing screwed portion of the plate spring as fulcrum.
A cartridge 23, with a magnetic tape 23a accommodated therein, has guide grooves 23b formed in both side faces thereof, as shown in FIG. 25B. The guide grooves 23b are guided by the guide members 21b and 21c to conduct the cartridge 23 into the apparatus 21.
In portions of a bottom plate 23c which constitutes the guide grooves 23b of the cartridge 23 there are formed cutout portions 23d.
For loading the cartridge 23 into the apparatus 21, first the front end portion of the cartridge is inserted manually in the direction of arrow B from an inlet 21e of the apparatus.
As a result, the front end portion of the bottom plate 23c of the cartridge 23 comes into abutment with the rollers 22b. But if the cartridge 23 is pushed into the apparatus 21 with a stronger force, the plate springs 22 deflect downward, whereby the rollers 22b are forced down.
By virtue of the resilience of the plate springs 22 the rollers 22b come into elastic contact with one end of each of the cutout portions 23d.
In this way one end of each of the cutout portions 23d is pressed in the direction of arrow A (45.degree.) by the rollers 22b, whereby the cartridge 23 is held in the interior of the apparatus 21 while it is prevented from coming off the apparatus. In this state, a magnetic head 24 and the magnetic tape 23a are in abutment with each other, now ready for recording and reproduction.
For unloading the cartridge 23 from the apparatus 21, the operator is required to pull a rear end portion 23e of the cartridge, which projects from the inlet 21e to the exterior of the apparatus, manually in the direction of arrow C against the biasing force of the plate springs 22, allowing the rollers 22b to be disengaged from the cutout portions 23d of the cartridge 23, whereby the cartridge can be removed from the apparatus 21.
In the above conventional apparatus 21, however, since the loading and unloading of the cartridge 23 are performed by hand, a fairly strong force (about 0.5 to 1 Kgf) is required against the biasing force of the plate springs 22. In order to facilitate the loading and unloading of the cartridge 23, the resilience of the plate spring 22 may be weakened, but in this case the force for holding the cartridge in the apparatus 21 becomes weaker, and when vibration or the like is exerted on the apparatus from the exterior, the magnetic tape 23a, which is in sliding contact with the magnetic head 24, may move, or the cartridge 23 may no longer be held in place. Once such a state occurs, it may become impossible to effect accurate recording and reproduction.